Yes. By default, sign-in's are allowed up to 10 minutes after the time the service is set to begin. You can increase or decrease this time by adjust the Kiosk settings in the Web Terminal:
1) Go to the Web Terminal pane inside of MSP.
2) Click on the "Web Terminal Settings..." button at the top of the Home tab.
3) In the settings window, click on the Sign-in Kiosk heading on the left.
4) Here you can adjust the numbers for, "Allow sign-in up to '60' minutes before and '10' minutes after the start of the service."
When finished, click OK in the settings window and then click the Commit Changes button at the bottom of the Web Terminal pane.